Handbook of Shaft Alignment Part 14 docx

One way to accomplish this measurement is to perform the double radial method (refer to Chapter 12). As shown in Figure 19.4, the dial indicator measurements can be taken on the inside bore of a cylinder rather than capturing the measurements on the outside of a cylinder (e.g., a shaft). Remember that you will have to compensate for the bracket sag that occurs at both the near and far indicators. You also have to be aware of the fact that you are reading an inside diameter and the sign (þ=À) of the measurement from the top to the bottom (or side to side) will be opposite of what it would be if you were measuring the outside diameter. View looking down the axis of rotation through clear shafts FIGURE 19.1 View through the axis of rotation. FIGURE 19.2 Motor and barrel. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 620 26.9.2006 8:43pm 620 Shaft Alignment Handbook, Third Edition For example, with the indicator set up to take a reading on the inside of the barrel, if the indicator is zeroed at the top of the inside of the barrel then rotated to the bottom and the dial indicator measured a þ20, the barrel appears to be ‘‘high’’ at that point. If instead, the indi- cator was set up to take a reading on the outside of the barrel, if the indicator is zeroed at the top of the outside of the barrel then rotated to the bottom, the dial indicator would measure a À20. Figure 19.5 shows the dimensions and double radial measurements that were taken on the motor and barrel. Figure 19.6 and Figure 19.7 show the side and top view alignment models. Centerline of barrel Centerline of rotation Centerline of barrel is in line only with the end of the motor shaft FIGURE 19.3 Pure angular misalignment of motor shaft and barrel centerline. 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 Near indicator Far indicator 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 Far indicator Taking measurements on the outside of a cylinder Taking measurements on the inside of a cylinder r o t a t e Near indicator FIGURE 19.4 Double radial method measuring outside and inside of cylinders. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 621 26.9.2006 8:43pm Bore Alignment 621 19.2 ALIGNING TWO HOLLOW CYLINDERS Next, let us examine how you would align two hollow cylinders with each other. The assumption is that the cylinders are perfectly straight (i.e., not bowed) and that the inside diameters of the cylinders are consistent along the full length of both cylinders. Either cylinder may, or may not, have the capability to rotate on an axis that is coincident with the centerline of its bore. The measurement device that we will use for this basic procedure is an optical jig transit (refer to Figure 6.11) held in position with an appropriate tripod or stand. The stand must have a translation slide and a precision vertical lift. The jig transit must also have an optical micrometer attached to the end of the telescope barrel (see Figure 6.15). The optical micrometer can be positioned to translate either the horizontal or vertical crosshair by rotating the micrometer through a 908 arc on the end of the telescope. The problem with doing this is that you run the risk of inadvertently moving the scope to a different line of sight, if you jar the scope when repositioning the optical micrometer. To reduce the need to rotate the micrometer, a coordinate optical micrometer enables the user to measure target offsets in both the vertical and horizontal planes without having to rotate a single axis micrometer 908 on the barrel of the telescope to capture both measurements as shown in Figure 19.8. An additional tooling that is required are bore sighting targets and fixtures to position and hold the sighting targets in the cylinders. Optical bore sighting targets are shown in 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 20 in.24 in.56 in. 5 in. 12 in. View looking east T B EW 0 T B EW 0 Near indicator +10 Ϫ36 +16 Sag compensated readings Ϫ20 +24Ϫ14 Far indicator Near indicator Far indicator FIGURE 19.5 Motor and barrel dimensions and measurements taken on bore using the double radial method. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 622 26.9.2006 8:43pm 622 Shaft Alignment Handbook, Third Edition Figure 19.8. These sighting targets are fabricated from nylon with an accurately painted patternofpairedlinesset908 apart precisely positioned from the center of the target. A small battery operated light source (e.g., a flashlight) can be used to illuminate the translucent target from behind, as this target will usually be placed inside a dark cylinder. Other sighting targets shown in Figure 19.9 are made out of thin wires or a pattern cut out of a thin piece of metal, which will allow you to view objects behind the target acting as if they were transparent. The see-through target is typically mounted as the nearest target to the jig transit Up Side view Scale: 10 in. 20 mils MotorBarrel T B E W 0 T B EW 0 Near indicator +10 Ϫ36 +16 Sag compensated readings Ϫ20 +24 Ϫ14 Far indicator FIGURE 19.6 Side view alignment model of motor centerline and barrel centerline. Scale: 10 in. 20 mils East Top view MotorBarrel T B EW T B EW Near indicator 0 +52 +380 Far indicator FIGURE 19.7 Top view alignment model of motor centerline and barrel centerline. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 623 26.9.2006 8:43pm Bore Alignment 623 enabling visual sighting of targets down range without having to move the see-through target from its position. The sighting targets will be placed at different points in the center of the cylinder and they do not have the capacity to automatically center themselves. Therefore a sighting target FIGURE 19.8 Coordinate optical micrometer. (Courtesy of Brunson Instruments, Kansas City, MO. With permission.) FIGURE 19.9 Translucent bore sighting target. (Courtesy of Brunson Instruments, Kansas City, MO. With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 624 26.9.2006 8:43pm 624 Shaft Alignment Handbook, Third Edition fixture is needed not only to hold the target in position, but also to center the target in the cylinder. This is true whether the sighting targets are visual targets like the ones shown in Figure 19.9 and Figure 19.10 or they are photodiode targets used with laser bore alignment systems. Fixtures similar to the ones shown in Figure 19.11 and Figure 19.12 are examples of adjustable target holding and centering devices needed for this process. The fixture on the left in Figure 19.11 uses eight setscrews, two at each 908 angle on the fixture to center and square the fixture in the bore of the cylinder. This fixture is held rigidly in a cylinder supported in FIGURE 19.10 See-through bore sighting target. (Courtesy of Brunson Instruments, Kansas City, MO.) FIGURE 19.11 Bore sighting target fixtures. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 625 26.9.2006 8:43pm Bore Alignment 625 bearings and the entire cylinder with the target installed can be rotated. The fixture on the right in Figure 19.11 is similar in design and function but with four bars that can move radially outward on guide bolts with ball bearings at each end of the bar that allow the entire target and fixture to rotate inside a nonrotatable cylinder. Figure 19.12 shows this fixture and a sighting target inside a barrel. An additional feature of this device is that the target can also be translated axially enabling several measurements to be taken along the entire length of the cylinder via a string that is used to pull the target through the barrel. 19.3 BASIC MEASUREMENT PRINCIPLES AND NOMENCLATURE Figure 19.13 shows the typically used coordinate system and jargon. Figure 9.14 shows the basic layout of the measurement process, the hollow cylinders with their bore centerlines shown as dashed lines, and some of the terminology and nomenclature that will be used in this procedure. As illustrated, the centerline of the bore of the near and far cylinders can be out of alignment with each other in both the vertical and lateral (sideways) directions. Although the jig transit telescope has the capability of being leveled within one arcsecond (0.001 in. 17 ft), it is important to understand that the centerlines of the bores of the two cylinders can be in line with each other (coincident) but not necessarily level. Leveled and aligned does not mean FIGURE 19.12 Bore target fixture inside a barrel. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 626 26.9.2006 8:43pm 626 Shaft Alignment Handbook, Third Edition the same thing (did I mention this before?). Therefore, the process of leveling the scope will not be discussed in this procedure. Figure 19.15 shows an angled view of the near and far cylinders with targets situated at each end of both cylinders. These targets must be accurately positioned to insure that they are truly in the center of the cylinder. To accomplish this, the target must be able to rotate through at least a 1808 arc and ideally through 3608 of rotation. This can be done in one of two ways: rotating the entire cylinder itself or rotating the target inside the bore of the cylinder. Figure 19.16 shows what the observer would see from the jig transit position looking at a target at the near end of the near cylinder. 19.4 CYLINDER ALIGNMENT PROCEDURE Aligning two cylinders with each other requires an eight-step process: z y x Roll Pitch Yaw FIGURE 19.13 Coordinate system and rotation nomenclature. Far adjustment plane of far cylinder Near adjustment plane of far cylinder Far adjustment plane of near cylinder Near adjustment plane of near cylinder Jig transit Jig transit Line of sight Line of sight Far cylinder Side view Top view Near cylinder FIGURE 19.14 Line of sight observing two misaligned cylinders in the side and top views. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 627 26.9.2006 8:43pm Bore Alignment 627 1. Install and center a see-through target at the near end of the near cylinder. To center the target in the bore of the cylinder, study and perform the tasks shown in Figure 19.17 through Figure 19.20. 2. Install and center a target at the far end of the near cylinder. Again, perform the tasks shown in Figure 19.17 through Figure 19.20 to center the target in the bore of the cylinder. 3. Buck in the jig transit line of sight to the targets installed in the near cylinder at the near and far ends. Refer to the ‘‘bucking in’’ procedure and perform the tasks shown in Figure 19.21. Near cylinder Far cylinder Far target of near cylinder Near target of near cylinder Far target of far cylinder Near target of far cylinder FIGURE 19.15 Near and far targets placed in near and far cylinders. FIGURE 19.16 Near target of near cylinder as observed from the jig transit. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 628 26.9.2006 8:43pm 628 Shaft Alignment Handbook, Third Edition 4. Install and center a target at either the far or near end of the far cylinder. Again, perform the tasks shown in Figure 19.17 through Figure 19.20 to center the target in the bore of the cylinder. 5. Install and center a target at the other end of the far cylinder. Again, perform the tasks shown in Figure 19.17 through Figure 19.20 to center the target in the bore of the cylinder. 6. Buck in the jig transit line of sight to the targets installed in the near cylinder at the near and far ends. Refer to the bucking in procedure and perform the tasks in Figure 19.21. Step 1. Prior to installing the target and fixture, roughly adjust the positioning screws to loosely fit (20–50 mils of clearance) the target and fixture in the bore. Slide the target into the cylinder and adjust the centering screws to snugly fit the target to prevent movement from occurring during rotation. Step 2. At the jig transit, focus on the target position and adjust the vertical and lateral tangent screws to aim the transit crosshairs at the target center as shown in the illustration below. Top Top Jig transit telescope crosshair Target in bore of cylinder FIGURE 19.17 Step 1 and step 2 for centering a target in a cylinder. Top Top Horizontal offset Vertical offset Rotate the target 180Њ Step 3. Rotate the target 180Њ and observe the target position through the jig transit telescope. Using the optical micrometer, measure the amount of vertical and lateral offset that exists between the target center and the center of the telescope crosshairs as shown in the figure below. FIGURE 19.18 Step 3 for centering a target in a cylinder. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 629 26.9.2006 8:43pm Bore Alignment 629 [...]... position of the laser beam on the surface of the detector Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 636 636 26.9.2006 8:43pm Shaft Alignment Handbook, Third Edition FIGURE 19.25 D630 Extruder system (Courtesy of Damalini, Molndal, Sweden With permission.) FIGURE 19.26 D630 Linebore system (Courtesy of Damalini, Molndal, Sweden With permission.) Piotrowski / Shaft Alignment. .. target 34 mils to the left Right Near cylinder-far support Top view Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 634 26.9.2006 8:43pm Shaft Alignment Handbook, Third Edition Near cylinder-near support Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 635 Bore Alignment 26.9.2006 8:43pm 635 scope on the near target, set the optical micrometer... telescope’s line of sight is parallel to the shaft (or roll) as shown in Figure 20.10 and Figure 20.11 Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 644 27.9.2006 1:30am 644 Shaft Alignment Handbook, Third Edition Line of sight Optical scale target A Optical scale target B Upper shaft (or roll) Optical jig transit or universal transit square Y Z Lower shaft (or roll)... Chapter 13, Chapter 14, and Chapter 17 For this particular example, we will assume that there is no off-line to running (OL2R) machinery movement in any of the components FIGURE 20.21 FixturLaser roll system (Courtesy of FixturLaser, Molndal, Sweden With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 654 27.9.2006 1:30am 654 Shaft Alignment Handbook, Third... 8:43pm Shaft Alignment Handbook, Third Edition ¨ FIGURE 19.29 Pruftechnik Boralign system (Courtesy of Pruftechnik, Ismaning, Germany With permission.) ¨ FIGURE 19.30 Pruftechnik Centralign system (Courtesy of Pruftechnik, Ismaning, Germany With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 639 27.9.2006 1:30am 20 Parallel Alignment Chapter 18 covered alignment. ..Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 630 630 26.9.2006 8:43pm Shaft Alignment Handbook, Third Edition Step 4 Adjust the position of the target inside the bore of the cylinder by alternately loosening and tightening the target fixture adjustment screws at the 12 and 6 o’ clock position to place the target half the total vertical offset distance measured... of universal transit square Translation distance Translation distance = (reading at scale E − reading at scale F) 3 scope to E E to F FIGURE 20.10 Top view of sighting the roll in the lateral direction Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 646 27.9.2006 1:30am 646 Shaft Alignment Handbook, Third Edition Scale target F Scale target E Scale target E Line of. .. 20.1, the position of a shaft or roll can be described by its pitch, roll, and yaw positions For shafts or rolls to be parallel, they would share the same roll, pitch, and yaw Pentaprism Laser FIGURE 20.18 Laser beam exits at a precise 908 angle with a pentaprism Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 652 27.9.2006 1:30am 652 Shaft Alignment Handbook, Third... transit square on its stand so that your line of sight is slightly to one side of one of the shafts (or roll) as shown in Figure 20.9 This transit will be referred to as the measurement transit Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 643 27.9.2006 1:30am Parallel Alignment 643 FIGURE 20.6 Jig transit (Courtesy of Brunson Instruments Co., Kansas City, MO With... rolls at the far end Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 641 27.9.2006 1:30am 641 Parallel Alignment Side view End view FIGURE 20.4 Centerlines of rotation are parallel in the y–z plane but skewed in the x–z plane 20.2 USING OPTICAL ALIGNMENT EQUIPMENT FOR ROLL PARALLELISM The extreme accuracy and versatility of optical alignment equipment makes it ideal . top view alignment models. Centerline of barrel Centerline of rotation Centerline of barrel is in line only with the end of the motor shaft FIGURE 19.3 Pure angular misalignment of motor shaft and. Near target of near cylinder as observed from the jig transit. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 628 26.9.2006 8:43pm 628 Shaft Alignment Handbook, . cylinder. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C019 Final Proof page 630 26.9.2006 8:43pm 630 Shaft Alignment Handbook, Third Edition 8. If the targets at the near and far ends of the